Evaluating Focal 18F-FDG Uptake in Thyroid Gland with Radiomics

Abstract

Purpose The aim of this study was to evaluate the ability of 18 F-FDG PET/CT texture analysis to predict the exact pathological outcome of thyroid incidentalomas. Methods 18 F-FDG PET/CT images between March 2010 and September 2018 were retrospectively reviewed in patients with focal 18 F-FDG uptake in the thyroid gland and who underwent fine needle aspiration biopsy from this area. The focal uptake in the thyroid gland was drawn in 3D with 40% SUVmax threshold. Features were extracted from volume of interest (VOI) using the LIFEx package. The features obtained were compared in benign and malignant groups, and statistically significant variables were evaluated by receiver operating curve (ROC) analysis. The correlation between the variables with area under curve (AUC) value over 0.7 was examined; variables with correlation coefficient less than 0.6 were evaluated with machine learning algorithms.Results Sixty patients (70% train set, 30% test set) were included in the study. In univariate analysis, a statistically significant difference was observed in 6 conventional parameters, 5 first-, and 16 second-order features between benign and malignant groups in train set (p < 0.05). The feature with the highest benign-malignant discriminating power was GLRLM RLNU (AUC:0.827). AUC value of SUVmax was calculated as 0.758. GLRLM RLNU and SUVmax were evaluated to build a model to predict the exact pathology outcome. Random forest algorithm showed the best accuracy and AUC (78.6% and 0.849, respectively). Conclusion In the differentiation of benign-malignant thyroid incidentalomas, GLRLM RLNU and SUVmax combination may be more useful than SUVmax to predict the outcome.

Comparison between Two Different Scanners for the Evaluation of the Role of 18F-FDG PET/CT Semiquantitative Parameters and Radiomics Features in the Prediction of Final Diagnosis of Thyroid Incidentalomas

“…A similar analysis was also performed by Aksu et al [22], who underlined how the semiquantitative PET/CT parameters and some shape-related, GLCM-related, GLRLMrelated and GLZLM-related RF obtained AUC values superior to 0.7. These findings were partially confirmed in our study, where the same parameters confirmed these good results, with the exception of semiquantitative parameters and shape-related RF.…”

“…Only a small amount of works that investigate the predictive role of radiomics in the evaluation of TIs at 18 F-FDG PET/CT are available in literature [21][22][23][24].…”

“…In this setting, the use of radiomics for the correct evaluation of every type of incidentalomas is waking increasing interest [19,20]. The case of TIs is not an exception and some works about the use of texture analysis for their correct classification have been produced [21][22][23][24]. However, similarly to semiquantitative parameters, the use of radiomics in this setting has given non-clarifying and initial results.…”

Incidental thyroid uptake on PET scanning: epidemiology, clinical significance, and management challenge

“…Several studies have evaluated the ability of SUV max to discriminate malignant from benign thyroid incidentalomas with conflicting conclusions (see Table 3). Mitchell et al [66] reported that using a SUV max cutoff value of 5.0 resulted in 60% sensitivity and 91% specificity for detection of malignancy, while Boeckmann et al [67] proposed a cutoff value of 4.2. Some reports noted a significant difference in SUV max between malignant and benign lesions (albeit frequently with substantial overlap), while others showed no difference at all.…”

Quantitative classification and radiomics of [18F]FDG-PET/CT in indeterminate thyroid nodules

“…In radiomics, large amounts of quantitative features are extracted from medical images, aiming to find stable and clinically relevant image-derived biomarkers that may provide new insights in tumour biology and guide patient management [18]. After a number of studies suggested that radiomic analysis could contribute to the differentiation of [ 18 F]FDG-positive thyroid incidentalomas, one study recently also indicated its potential in the diagnosis of indeterminate nodules [19][20][21][22][23][24].…”